Nutritional Profile Analysis of Red Bean Tempeh Fermented Using <i>Rhizopus Oligosporus </i>at Different Time

Abstract

Investigation of non-soybean legumes as raw material for making tempeh is very important to be carried out continuously considering soybean production tends to decline from year to year. This study aims to analyse the potential of red bean seeds as raw material for tempeh and changes in their nutritional profile when fermented at different fermentation times. The red beans were soaked in water overnight at room temperature and then boiled for 20 minutes. After boiling, the red beans were drained and then fermented for 36, 48, and 60 hours using a suspension of <i>Rhizopus oligosporus</i> with a weight of 2 g for each 1000 g of red beans. Red bean tempeh was analysed for quality using test parameters including physical appearance (color, texture, and aroma) and nutritional profile (calorie value, ash, water, crude fiber, fat, protein, and carbohydrate content). The physical appearance and nutritional profile of red bean tempeh were compared with those of soybean tempeh, while the quality of tempeh was compared with Indonesian national standards for tempeh. The results showed that the length of fermentation time significantly affected the nutritional profile of tempeh. Red bean tempeh fermented for 48 hours had a nutritional profile including energy, water, ash, protein, fat, carbohydrate, and crude fiber content of 201.59 kcal/100 g tempeh, 61.97%, 1.18%, 16.19%, 10.98%, 8.29%, and 1.13%, respectively. The physical appearance and nutritional profile of red bean tempeh have met the tempeh quality requirements issued by the Indonesian national standard for tempeh. Therefore, red bean seed appears to be as good as raw materials for tempeh production.